Add release notes about keyword arguments.

readme.md

@@ -24,6 +24,8 @@ Please see the [project releases](https://socketry.github.io/protocol-http/relea
 
 ### Unreleased
 
+  - [`Request[]` and `Response[]` Keyword Arguments](https://socketry.github.io/protocol-http/releases/index#request[]-and-response[]-keyword-arguments)
+
 ## See Also
 
   - [protocol-http1](https://github.com/socketry/protocol-http1) — HTTP/1 client/server implementation using this

releases.md

@@ -1,3 +1,17 @@
 # Releases
 
 ## Unreleased
+
+### `Request[]` and `Response[]` Keyword Arguments
+
+The `Request[]` and `Response[]` methods now support keyword arguments as a convenient way to set various positional arguments.
+
+```ruby
+# Request keyword arguments:
+client.get("/", headers: {"accept" => "text/html"}, authority: "example.com")
+
+# Response keyword arguments:
+def call(request)
+	return Response[200, headers: {"content-Type" => "text/html"}, body: "Hello, World!"]
+end
+```